Latch mechanism for container bottom discharge door



t- 13, 1964 s. BOLLING ETAL 3,152,824

LATCH MECHANISM FOR CONTAINER BOTTOM DISCHARGE DOOR Filed Oct. 10, 1961 4 Sheets-Sheet 1 I a INVENTORS 2 Roberi a 5mm;

i Oct. 13, 1964 5, o m ETAL 3,152,824

LATCH MECHANISM FOR CONTAINER BOTTOM DISCHARGE DOOR Filed Oct. 10, 1961 4 Sheets-Sheet 2 M INVENTORS E0661? 5? BaZZz' Graeme Pl zz ATTORNEY Oct. 13, 1964 R. s. BOLLING ET-AL 3,152,824 men MECHANISM FOR CONTAINER BOTTOM DISCHARGE DOOR Filed Oct. 10. 1961 v 4 Sheets-Sheet :5

Oct. 13, 1964 R. s. BOLLING EI'AL 3,

men MECHANISM FOR CONTAINER BOTTOM mscmacs DOOR 4 Sheets-Sheet 4 Filed Oct. 10, 1961 INVENTORS' Baker? )5 BoZZz'n VIIIIIIIIIII IIII Graeme .D. Plmf BY. ,4 I ORNEY United States Patent 3,152,824- LATH MECHANlSli/l FOR CONTAENER BQTTGM V DESCHARGE DUQR Robert S. Bolling and Graeme D. Plant, both of Napa, aiif., assignors to Kaiser Steel Corporation, @airiaud, Calif., a corporation of Nevada Filed Oct. ltd, 1961, Ser. No. 144,198 12 Claims. (Cl. 292-216) This invention relates to cargo containers provided With discharge gates or doors, such as bottom discharge gates or doors, for permitting quick and complete discharge of the contents of the containers. More particularly, it is concerned with a transportation container for bulk materials and the like wherein a novel latch mechanism is employed for locking and unlockingthe discharge gate for the container.

I Accordingly, it is a primary purpose of this invention to provide a transportation container having a discharge gate wherein an improved latching mechanism is employed for holding the discharge gate in a closed position.

Other purposes and advantages of the instant invention will become more apparent from a review of the following detailed description when taken in conjunction with the appended drawings wherein;

FIG. 1 is an elevational view of one side of a transportation container provided with the novel latching mechanism of the instant invention and with certain parts broken away and with other parts being shown in dotted lines;

FIG. 2 is a fragmentary sectional view with parts removed of a portion of the container shown in FIG. 1 when taken along line 2-2 thereof and discloses in more detail the latching mechanism of the instant invention used to hold the container closure gate in a locked position;

FIG. 3 is a view similar to FIG. 2 and discloses the I location of the various elements of the latch mechanism during the time the latch mechanism is operated to release the closure gate;

FIG. 4 is a sectional View generally taken along the line 44 of FIG; 2; and

FIG. 5 is a fragmentary sectional viewsimilar to FIG. 2 and discloses a slightly modified form for the latch mechanism.

With further reference to the drawings, and in particular FIGS. 14, the closure gate latch assembly or mechanism 1 is utilized with a transportation container 2 used to carry bulk materials and the like. This container is provided with a plurality of sides 3 which can be reinforced in a manner conventional in the art by side stiffeners i. Stiffeners 4 are welded or otherwise secured to the sides 3. As indicated in the drawings, the upper portions 3' of sides 3 can be somewhat tapered in order to facilitate the discharge of the contents of the container during dumping. If desired, two opposing sides 3 of the container can be provided with conventional bales or hook-shaped elements 5 which can be engaged by lifting chains or conventional hoisting apparatus for the purpose of transporting the container along with its contents from place to place. 1

The bottom of the container 2 is provided with a conventional discharge opening 6. A closure gate or door 7 is employed for the purpose of closing this discharge opening o and as indicated in FIG. 1 this door is suitably hinged to one of the sides 3 of the container 2 by means of several hinge assemblies d. Any suitable hinge assembly 8 can be used. For example, as indicated in FIG. 1, the hinge assembly may comprise a bracket 9 which is welded or otherwise secured to the side 3. Bracket 9 is provided with an opening 10. The closure gate or door 7, in turn, is provided with a pair of spaced brackets 11 having openings 12 therein. When a pin 13 is inserted 3,l52,824 Patented Get. 13, 1964 and locked in the aligned opening 10 of bracket 9 and openings 12 of bracket 13, the closure door 7 is then hingedly connected in a manner conventional in the art to the container 2. y

it will be further observed by referring to the drawings, and in particular FIGS. 2-4, that the door assembly 7 is so constructed that it is provided with a fioor or deck plate 15. One of the side members 16 of door assembly '7 is advantageously roughly Z-shaped in cross section while the other sides 16' of door assembly 7 are L-shaped. One of the edges 17 of the deck plate 15 projects outwardly and beyond the bottom 18 of a side 3. This edge 17 combines with the top flange 19 of the Z-shaped side member '16 to form a latch engaging tongue 12'.

Tongue 1% is advantageously located on the side of the container 2 which is opposite to the side of the container to which the closure of the gate is pivotally attached and tongue 19' is adapted to be inserted in the mouth 20 of the latch member 21. I

Latch member 21 is pivotally mounted between a pair of side reinforcing members 4 by means of the pin 22 inserted in bushing 23 located in the opening 24 of the latch member 21, as well as in the trunnion or journalbearing members 25 welded or otherwise secured to the inside surfaces of the two reinforcing elements 4. The ends of pin 22 project through the openings 26 in the reinforcing elements 4 and are locked to the reinforcing elements 4 by means of conventional cotter pins 27.

It will be further observed by reference to the drawings that the latch member 21 is advantageously eccentrically arranged upon the pin 22 whereby the major portion of themass of the latch member 21 is disposed on the lefthand side of the pin 22 as viewed in FIGS. 2 and 3 whereby when the latch member 21 is released or placed in an unrestrained condition it will tend to fall or pivot in a counterclockwise direction.

Latch member 21 is provided with a projecting shoulder element 39. Shoulder element 3% has an arcuate surface 7 31 at the lower portion thereof, which serves as the upper part or upper lip of the mouth 20. The upper part of the latch member 21 is provided Wlih a head 32 having an upper outer arcuate or cam surface 33 and a slotted and somewhat arcuate opening 34. The are of the arcuate surface 33 is advantageously drawn along a radius, the

axis of which substantially coincides with the axis of the element 3%} is a detent holding recess 35. Recess 35 is .formed by the planar and inclined surface 36 of the shoulder element St) and the inner arcuate surface 37 on the forward part of the head 32. Arcuate surface 37 also intersects-the upper arcuate surface 33 of the head 32.

Disposed within the slotted opening 34 is a pivot pin 49. Pivot pin 4% is attached to the same two reinforcing members 4 as and in a similar fashion to pivot pin 22, so that it is maintained in a fixed position. Thus, pivot pin 40 is journalled in the journal-bearing members 42 affixed to the inside surfaces of the reinforcing elements 4. Bearing members 42 are disposed above and in spaced relationship to the bearingmemb'ers 25. Cotter pins 43 are used to hold the pin 40 in position. Pivotally affixed to pin 4-0 intermediate the journal or hearing members 42 are the forks 45 of the lever arm 46. These forks project inwardly toward the body of container 2 whereby the lever arm can be said to be somewhat L-shaped in configuration. Freely journalled between the forks 45 adjacent the free ends thereof is a detent roller 48. Roller 48 is adapted upon movement of lever arm 46 inwardly or in a counterclockwise direction to fit in the detent holding recess 35. Upon the clockwise movement of lever arm 46 outwardly or to the right as viewed in the drawings, roller 48 is adapted to move along inner arcuate surface 37 until it contacts the upper arcuate surface 33 of the head 32 of latch member 21, all in a manner to be described more fully hereinafter. A locking pin 49 inser-table in suitable openings in the reinforcing elements 4 can be employed if desired to hold the lever arm 46 in a fixed inward position during the time it is desired to have the latch member 21 held in a locked position. The latch assembly is completed by means of a lower tension spring 5i), one end of which is anchored to the lower part of the latch member 21 adjacent mouth 29 and the other end of which is anchored to the angleshaped bracket member 51' affixed to the same pair of reinforcing members 4 to which the latch member 21 is afiixed.

If desired, a further tension spring 52, the function of which will be described more fully hereinafter, can be employed, one end of which is secured to the L-shaped lever arm 46 and the other end of which is anchored to a side wall 3 of the container 2.

The operation of the latching mechanism or assembly 1 is as follows: At the time that the latch member 21 is in the position shown in FIG. 2 or in the locking position, the lever arm 46 assumes an upright position having been pivoted to that position on the pivot pin 40. At the same time, the detent wheel or roller 48 rests in the detent holding recess 35 with the periphery of the wheel 48 resting partially on the arcuate surface 37 of the head 32 of latch member 21 and partially on the planar surface 36 of the shoulder element St) of latch 21. When it is desirable to release the door or closure gate 7, the lever arm 46 is pivoted to the right or in a clockwise direction about pivot pin 40. This causes wheel 48 to ride up the inner arcuate surface 37 until the wheel 48 contacts the upper arcuate surface 33 of latch head 32. As the wheel 43 reaches surface 33 the weight of the door 7 is allowed to act upon the latch 21 because wheel 43 is no longer in a position to restrain pivotal movement of latch member 21. The weight of door '7 then causes the latch member 21 to be pivoted to the left or in a counterclockwise direction about pivot pin 22 withhead 32 then moving relative to pin through the medium of the elongated slot 34 of the latch member 21 and with wheel 48 riding along surface 33. As the latch member 21 moves in a counterclockwise direction, the bottom restraining lip 31' of the mouth 20 moves out of the way as indicated in FIG. 3 and allows the door 7 to drop free of the latch member 21. Contemporaneously with this movement of the latch member, the tension spring 5i) exerts a certain amount of pull on the latch member 21 thereby facilitating the counterclockwise movement of member 21.

The door 7 is closed in the following fashion. If the container is suspended from a hoisting apparatus, the hoisting apparatus merely lowers the container to the floor or ground until the door 7 contacts the floor or ground. This causes the door to move upwardly and into contact with the curved upper lip 31 of the mouth 20,

thereby forcing the latch member 21 to move toward the right or in a clockwise direction. At the same time, the head 32 of member 21 slides to the right relative to pivot pin 46 through the medium of the slotted opening 34. In the meantime, roll-48 rolls across the arcuate surface 33 until it drops down and into contact with the arcuate inner surface 3'7 coming to rest in the detent holding recess 35 where it assumes its normal latch restraining position.

' At this time, of course, during its clockwise movement the latch member 21 operates against the action of th'e tension spring 50, the forces exerted by the closing of door '7 being suificient to overcome any counteracting force exertedby spring 59. As noted above, a second tension spring 52 can also be used. Spring 52 advantageously acts to hold roller 48 in contact with surface 33 during the unlatching operation and because of its position exerts relatively no counteracting force on spring 59. However, as lever 46 is moved toward the left,

spring 52 functions to facilitate this movement of lever arm 46 and a dropping of roller 48 into the detent holding recess 35 as roller 48 reaches the inner end of arcuate surface 33, whereby spring 5'2 can be said to more or less assist in snapping roller 48 into the detent holding recess 35. It is to be understood, of course, that spring 52 is not sufficiently stiff to prevent the manual movement of lever arm 46 outwardly at the time the roller 48 is disengaged from recess 35. After the lever arm 46 has been moved to a closed position, a locking pin 49 is then inser-ted in suitable openings in members 4 so as to prevent any accidental operation and release of the latch assembly 1.

As noted in the drawings, the arc of inner arcuate surface 37 is drawn along a radius the axis of which coincides with the axis of pin 40 in order to facilitate movement of roller 48 along surface 37 during opening of the latch mechanism while at the same time preventing any forces exerted by the load on lip 19' of door 7 from causing displacement of the roller 48 from the detent recess 35 during the locking of the latch mechanism 1. The arc of surface 33 is advantageously drawn along a radius, the axis of which coincides with pin 22 in order for roller 48 to move freely without binding across this surface 33 in either'direction during opening and closing of the latch mechanism 1.

In a further advantageous embodiment of the inven tion and as indicated more particularly in FIG. 5, the lever arm 46 is provided at the bottom with vertically disposed forks 45' pivotally secured to fixed pin 40. Located intermediate forks 45 is the bifurcated and L-shaped arm 60. Wheel or roller 48' is mounted between the forks 61 on the stem 62 of arm 60 with stem 62 in turn being freely pivoted on pin 40' intermediate the forks 45 of lever arm 46. The bifurcated leg 63 of arm 6t? is adapted in the locked position of latch assembly 1' to loosely abut and test against the forks 45 of lever arm 46. The operation of latch mechanism 1' is generally the same as latch mechanism 1, except for the interaction of bifurcated arm 60 and lever 46'. Thus, when lever arm 45 is moved to the right, as shown in the drawings, it will due to the engagement of the bridge portion 65 on the leg 63 of bifurcated arm as with the forks 45 of armgi cause clockwise movement of arm 60 and engagement of wheel 4-8 with surface 33' of the head 32' of the latch member 21'. Contrary to the. operation of latch mechanism 1 when lever arm 46' is restored to its position of rest by means of spring 52', roller 48' will remain in engagement with surface 33'. In other words, the return movement of lever arm 46' is independent of the return movement of bifurcated arm of Bifurcated arm 60 is returned to a locking position along with roller 48 due to the weight of roller 48' as it moves into the detent holding recess 35. The weight of roller 48 and length of the stem 62 issuch as to produce an unbalancing of the bifurcated leg portion 63 of the'arm 69. Finally, both of the latch mechanisms 1 and 1' can be provided if desired with an adjustable stop pin 7th which projects into the slot 34 or 34' for limiting the amount of movement of either latch member 21 or latch member 21', as the case may be.

Advantageous embodiments of the invention have been herein disclosed and described. It is obvious that various changes and modifications may be made therein without departing from the spirit and scope thereof, as defined in the appended claims, wherein, What is claimed is:

What is claimed is:

1. A transportation container for bulk goods and the like, said container being provided with side walls, a discharge opening and a closure gate for closing said discharge opening hingedly connected to a side wall of the container, said gate having a tongue on one side thereof, locking meansfor engaging said tongue and retaining the closure gate in a closed position, said locking means com prising a latch member pivotally affixed to a side wall of the container, said latch member being provided with a the closure gate, a shoulder element projecting outwardly toward the body of the container and a head having an upper arcuate outer surface at the top thereof and another inner arcuate surface at the forward portion thereof, said latch member being further provided with a detent-holding recess formed by said shoulder element and said inner arcuate surface, lever means provided with a detent wheel which is adapted to be removably inserted in the detent-holding recess of the latch member upon a predetermined counterclockwise movement of said latch member for holding the latch member in a closed position and the tongue of the closure gate fixedly in the mouth of said latch member, the arc of said upper arcuate outer surface of the head being drawn along a radius the axis of which coincides with the axis of said latch member and the arc of said upper arcuate outer surface of said head wherein said lever means comprises a pivot pin, a lever arm and a separate bifurcated arm, the detent wheel being aflixed to said bifurcated arm and said lever arm and bifurcated arm being each independently fulcrumed on the said pivot. pin.

4-. A transportation container for bulk goods and the like, said container being provided with .side walls, a discharge opening and a closure gate for closing said discharge opening hingedly connected to a side Wall of the container, said gate having a tongue on one side thereof, locking means for engaging said tongue and retaining the closure gate in a closed position, said locking means comprising a latch member pivotally affixed to a side wall of the container, said latch member being provided with a mouth at the bottom thereof for receiving the tongue of the closure gate, a shoulder element projecting outwardly toward the body of the container and a head having an arcuate outer surface at the top thereof and another inner arcuate surface at the forward portion thereof, said latch member being further provided with a detent-holding recess formed by said shoulder element and said inner arcuate surface, lever means provided with a detent wheel which is adapted to be removably inserted in the detent-holding recess of the latch member upon a predetermined counterclockwise movement of said latch member for holding the latch member in a closed position and the tongue of the closure gate fixedly in the a mouth of said latch member, the head of said latch memher being provided with a slotted opening and said lever means being fulcrumed in such slotted opening.

5. A transportation container as set forth in claim 4 wherein the upper lip of the'mouth of the latch member 1 is r d.-

it 6. A transportation container as set forth in claim 4 wherein said latch member is provided with adjustable stop pin means which project into the slotted opening of the head of the latch member.

7. A transportation container as set forth in claim 6' wherein said lever means comprises a lever arm and a bifurcated arm with the detent wheel being aflixed to said bifurcated arm and said lever arm and said bifurcated arm being each independently fulcrumed in the slotted opening of the latch member head.

8. A transportation container for bulk goods and the like, said container being provided with side walls, a discharge opening and a closure gate for said discharge opening hingedly connected to a side wall of the said container, said gate having a tongue projecting from one side thereof, and locking means engageable with the tongue of the said closure gate for retaining said gate in .a closed position, said locking means comprising a latch member pivotally and eccentrically affixed to one of the side walls of the container, said latch member having a mouth at the bottornthereof for receiving the tongue of the closure gate, a shoulder element projecting inwardly toward the body of the container, a head provided with a slotted opening, an arcuate outer surface at the top of the head and another inner arcuate surface at the forward portion thereof, said latch member also having a detent-holding recess formed by said. shoulder element and said inner arcuate surface, lever means provided with a detent wheel which is adapted to be removably insertable in the detent-holding recess of the latch member upon a predetermined counterclockwise movement of said latch member whereby the latch member will be held in a closed position and the tongue of the closure gate will be held in the mouth of the latch member and said lever means being fulcrumed in the slotted opening of said head.

9. A transportation container as set forthin claim 8 wherein the axis of the arc of the arcuate surface of the head of the latch member coincides with the pivotal axis of the latch member.

10. A transportation container as set forth in claim 8 wherein the axis of the arc of said inner arcuate surface coincides with the pivotal axis of the lever means.

11. A transportation container as set forth in claim 8 wherein said latch member is provided with spring means normally urging said latch member to an open position.

12. A transportation container as set forth in claim 8 wherein said slotted opening in the head of the latch memher is provided with an adjustable stop pin means.

References Cited in the file of this patent UNITED STATES PATENTS 2,544,682 Hilgeman Mar. 13, 1951 2,697,092 Johansson Dec. 14, 1954 2,881,021 Jacobson Apr. 7, 1959 

1. A TRANSPORTATION CONTAINER FOR BULK GOODS AND THE LIKE, SAID CONTAINER BEING PROVIDED WITH SIDE WALLS, A DISCHARGE OPENING AND A CLOSURE GATE FOR CLOSING SAID DISCHARGE OPENING HINGEDLY CONNECTED TO A SIDE WALL OF THE CONTAINER, SAID GATE HAVING A TONGUE ON ONE SIDE THEREOF, LOCKING MEANS FOR ENGAGING SAID TONGUE AND RETAINING THE CLOSURE GATE IN A CLOSED POSITION, SAID LOCKING MEANS COMPRISING A LATCH MEMBER PIVOTALLY AFFIXED TO A SIDE WALL OF THE CONTAINER, SAID LATCH MEMBER BEING PROVIDED WITH A MOUTH AT THE BOTTOM THEREOF RECEIVING THE TONGUE OF THE CLOSURE GATE, A SHOULDER ELEMENT PROJECTING OUTWARDLY TOWARD THE BODY OF THE CONTAINER AND A HEAD HAVING AN UPPER ARCUATE SURFACE AT THE TOP THEREOF AND ANOTHER INNER ARCUATE SURFACE AT THE FORWARD PORTION THEREOF, SAID LATCH MEMBER BEING FURTHER PROVIDED WITH A DETENT-HOLDING RECESS FORMED BY SAID SHOULDER ELEMENT 